High Impact Polystyrene (HIPS)
HIPS is a grade of PS. The graph bars on the material properties cards below compare HIPS to: styrenic plastics (top), all thermoplastics (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
1.9 GPa 0.28 x 106 psi
Elongation at Break
40 %
Flexural Strength
62 MPa 9.0 x 103 psi
Impact Strength: Notched Izod
45 J/m 0.85 ft-lb/in
Poisson's Ratio
0.41
Tensile Strength: Ultimate (UTS)
32 MPa 4.6 x 103 psi
Thermal Properties
Glass Transition Temperature
100 °C 210 °F
Maximum Temperature: Autoignition
420 °C 780 °F
Maximum Temperature: Decomposition
330 °C 620 °F
Maximum Temperature: Mechanical
70 °C 160 °F
Specific Heat Capacity
1400 J/kg-K 0.33 BTU/lb-°F
Thermal Conductivity
0.22 W/m-K 0.13 BTU/h-ft-°F
Thermal Expansion
80 µm/m-K
Vicat Softening Temperature
110 °C 220 °F
Electrical Properties
Dielectric Strength (Breakdown Potential)
18 kV/mm 0.7 V/mil
Electrical Resistivity Order of Magnitude
14 10x Ω-m
Otherwise Unclassified Properties
Density
1.0 g/cm3 65 lb/ft3
Limiting Oxygen Index (LOI)
18 %
Water Absorption After 24 Hours
0.080 %
Common Calculations
Stiffness to Weight: Axial
1.0 points
Stiffness to Weight: Bending
40 points
Strength to Weight: Axial
8.5 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
0.15 mm2/s
Thermal Shock Resistance
15 points
Followup Questions
Further Reading
ASTM D883: Standard Terminology Relating to Plastics
SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000
Modern Plastics Handbook, Charles A. Harper (editor), 1999
Plastics Materials, 7th ed., J. A. Brydson, 1999
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015